1. Field of the Invention
This invention relates generally to engineering modeling software, and particularly, to simplification of engineering models.
2. Background Information
Simplification of engineering models, and in an illustrative case, a water distribution system, has been an essential process to establishing a sound computer model that represents the physical and hydraulic characteristics of the water system. This is primarily due to the large size of a real water system and the use of a computer model to simulate the system. A water distribution system usually consists of hundreds of thousands of hydraulic elements including pipes, valves, pumps, tanks and reservoirs. It is not possible or necessary to include every element in the computer model. For instance, an operation manager (as opposed to a design engineer, for example) is typically concerned about how to operate the control components, such as pumps and valves, rather than the pressures at every junction, to meet the water supply requirement at the minimum energy cost, thus an operation model needs to be built to capture the characteristics of system operation, but does not need to include every single pipe line. Therefore, effectively simplifying a hydraulic network is essential to achieving a sound computer model representation of a real system and a more efficient approach for water distribution modeling.
Conventionally, there have been two approaches developed for network simplification, namely, element-by-element and parameter-fitting simplification. The former approach proceeds element-by-element by applying the techniques of data scrubbing, branch trimming, series pipe removal, parallel pipe replacement, and equivalent pipe for loop replacement to reduce the size of an original water distribution system to a manageable dimension. This is often referred to as “skeletonization.” These processes can be repeated until the desired simplicity is reached. Skeletonization can be guided by heuristic rules including shifting the small diameters and replacing the adjacent nodes of similar pressures with one node. However, these heuristics have not always preserved the integrity and hydraulic accuracy of a network. Thus, the resulting simplified network model does not behave in a manner consistent with the original network model.
An exact simplification cannot typically be achieved by applying an element-by-element approach, even for a simple system. In addition, it would be preferable to provide a method of verifying the final accuracy of the simplified network that resulted from the stepwise skeletonization.
There remains a need, therefore, for a method and system that provides a simplified model, but which maintains the integrity of the network while accurately reinstating the hydraulic behavior of the original network, and allowing for verification of the accuracy of the simplification.
It is thus an object of the present invention, to provide a parameter-fitting approach to hydraulic network simplification to improve the overall results of the simplification and to overcome the limitations of element-by-element simplification.